The present invention relates to centralized monitor and control systems for remotely monitoring the conditions of the alarming terminal ends from the receiving end, or selectively controlling a plurality of controlled devices at the alarming terminal end from the receiving end or performing both of these functions, and more particularly the invention relates to an improvement in such system whereby the number of link lines for connecting the receiving end with the alarming terminal end is reduced.
In known monitor and control systems such as fire alarm systems, it has been the usual practice to connect the receiver of the system to the alarm transmitters at the alarming terminal end as well as many other disaster preventing devices by means of a large number of link lines which provide one-to-one paired connection between the receiver and the individual devices. As a result, where the processing of data from a large number of monitoring points or the selective control of a large number of control points in a complex, large building or the like is effected centrally at a remotely located centralized system, a very large number of link lines are required to connect the receiver to the large number of monitoring points and control points, thus unavoidably resulting in a great increase in the wiring cost.